The disclosure relates generally to an oil recovery system, and more particularly to a system and method for a thermal assisted enhanced recovery of oil.
Enhanced oil recovery (herein also referred as “EOR”) is used to mobilize the trapped oil in pores held up by viscous and capillary forces, and increase the amount of oil extraction from an oil well. In a typical EOR technique, a medium is injected to an oil field. The injected medium pushes the crude-oil towards the oil well, such that a mixture of oil and water/injection medium can be extracted from the oil well. Typically, the medium includes items such as miscible solvents, polymer, microbes, liquid carbon dioxide, hydrocarbon, and thermal energy such as fire flood, and steam, for example.
In one example of thermal EOR, oil is separated from an extracted mixture of oil and water. The produced water is processed and reused as feed water for the steam generation. However, the quality of the resulting water does not meet the required standard for an efficient drum boiler, due to a high percentage of impurities such as salts, solvents, or the like. When such water is used as a feed water, generally a once through steam generators are used. However, there will be a very large percentage of blow-down due to the presence of impurities. Further, the traditional EOR techniques results in loss of energy due to a high percentage of blow-down.
Thus, there is a need for an improved system and method for recovering oil from an oil well.